Monopoles on demand

摘要

Elusive magnetic monopoles - regions of lone north or south magnetic charge - have recently been detected in very cold 'spin ices', a class of tetrahedral crystals. Now Will Branford and his colleagues at Imperial College London have created monopoles atrnroom temperature, and imaged them directly.rnThe team arranged cobalt nanorods into a honeycomb lattice on silicon to form a two-dimensional analogue of the spin-ice structure. By applying magnetic fields they disrupted the bars' magnetic alignments, so that regions of north or south magnetic charge were trapped at points where three bars met.